1. Field of the Invention
The invention relates in general to special process for manufacturing a multi-layered adhesive tape roll, wherein the flat piece of multi-layered adhesive tape is easily portable adhesive tape capable of saving space for convenient carrying.
2. Description of the Related Art
Conventional adhesive tapes usually are designed with circular inner core, such as paper core, plastic core or similar core. Recent developments have led to the flat adhesive tapes 12. Hollow orthogonal flat plastic tubes are made by ejection molding or hollow square flat paper tubes are designed by bending card board, as reference number 10 shows in FIG. 1. Adhesive tape is then unwounded out from jumbo roll and slitted into a desired tape. The tubes 10 are individually winded up into the flat adhesive tapes 12. However, such a manufacturing method requires a long working time and higher cost. Moreover, this kind of flat adhesive tape cannot provide necessary special physical properties, for example, super-transparence and coherence, due to the occurrence of trapped bubbles when the adhesive tapes are individually winded up.
If the conventional adhesive tapes are compressed directly to become the flat adhesive tape, the inner tubes are distorted and the outside surface of the adhesive tapes is deformed by applied stress. Moreover, a strong rebound force remains in the distorted material, for example, the tube and tape. The more distortion occurs in a short time, the more rebound force there is. Besides, due to intrinsic properties such as visco-elasticity and memory of the substrate and adhesive layer of the adhesive tape structure, after the compression stress is removed the relaxation of the structure accompanied by a rebound force drive the adhesive tape to a stable state. The rebound force drives the adhesive tape to regain the tape""s original shape. The strength of the rebound force depends on the deformation degree on the each position of the adhesive tape. The strength of the rebound force further depends on the thickness of the substrate, mechanical strength of the substrate, physical properties of the adhesive layer, adhesion, total length, central length of the symmetric plane (internal diameter before performing the compression step), and the winding up tension of the adhesive tape.
The manufacturing process of the easily portable and multi-layered adhesive tape of the present invention is suitable for flatting any adhesive tape roll and capable of automatic production and manufacturing a high quality flat adhesive tape.
The flat piece of easily portable and multi-layered adhesive tape, that is a flat adhesive tape, of the present invention is mainly made by flatting the non-flat and multi-layered adhesive tape roll having a circular shape or other shapes. During the flatting process, the non-flat and multi-layered adhesive tape roll is compressed and cohered symmetrically, or a stiff interfacial layer having or lacking high adhesion property is provided before the non-flat and multi-layered adhesive tape is compressed. The existence of the stiff interfacial layer produces an extending force along the symmetric plane of the easily portable flat adhesive tape. This extending force partially diminishes the rebound force, which causes the deformation of the flat adhesive tape. If the total length of the flat adhesive tape is not very long, the rebound force is not very large, either. Therefore, the non-flat adhesive tape without a paper core can be compressed and cohered directly through both innermost adhesive surfaces or a stiff and solid interfacial layer located in the innermost portion of the flat adhesive tape, so that a beautiful and easily portable flat piece of adhesive tape is formed. The stiff and solid interfacial layer is, for example, adhesive, cardboard, plastic plate, metal slice, or combination, or the like. When the strength of the flat adhesive tape is increased using, for example, increasing the thickness of the substrate with a high mechanical strength, increasing the total tape length, or reducing the inner diameter, the rebound force is also increased. Under such circumstances, a layer of high adhesion material can be applied to the symmetric plane of the adhesive tape. The layer of high adhesion material is, for example, high glass transition temperature polymeric materials, thermoset materials, hot melt materials, or ultra-violet curable adhesive materials for ensuring the symmetric cohesion of the innermost portion of the flat adhesive tape. The preferential material of the high adhesion material is a cyanoacrylate adhesive or an epoxy adhesive, having a high cross-linking density property after curing. After solidification for any mentioned adhesion material the high adhesion material not only provides adhesion functionality but also provides an extension force for sustaining the flat adhesive tape and partially offsetting the rebound force. Of course, if the high adhesion material is combined with the stiff interfacial layer, the rebound force is further offset, and the stability of the flat adhesive tape is therefore increased.